Machine tool for metal turning and the like



April 2, 1946.

MACHINE H. J. LQNGLEY TOOL FOR METAL TURNING AND 233 LIKE Filed Se t. 9, 1942 Sheets-met l Aprifi 2, m H, J. LONGLEY v 293979793 v MACHINE TOOL FOP. METAL TURNING AND THE LIKE Filed Sept. 9, 1942 5 Sheets-Sheet 2 www- Apzii 2,1946. H. J. LONGLEY 5 3 MACHINE TOOL FOR METAL TURNING AND THE LIKE Filed Sept. 9, 1942 S-Sheet -Sheet 3 pa. jny ff/ I. 2 M 7 Patented Apr. 2, 1946 um'rso STATES PATENT oFFic-B Herbert Joseph Longley, Catcutta,iflrltishlndia Application 111 December 20, 1941 This invention relates to a machine tool-adapted to take the place :of e..;simple :lafiheused .in workshops for metal machining and cutting off purposes,andmioritsohiectio providean improvedmachine :Eor these purposes working in a novel manner:

As usually constructed 1a lathe eonsists of a head-stock and a bed which must the carefully machined to insure *the accuracy of the lathe. On this bed is mounted :a saddle which-is adapted to slide thereonwand'which carries the tools. This saddle can move horizontalhrzparallel the axis :of the lathe, and'in addition a transverse slide is mounted which moves the tool :at right angles to'the ilongimdinal .axis of the head-stock in a horizontal plane.

In the improvedmachinetoolaccordingito this invention however is no bad whichv has to he faced up accurately, but according to azpreferred embodiment of the. imxentionrthis ismplaced by a single straight turned rod, forming a pilot or directingshaftfiiled parallel to the axis of rotation. of the work-piece fixed in. themachine. There iszno saddle or transverse slide as these are no longer necessary in this type of. machine as the tool carrying member or mmloers, conveniently in the form of an apron m" aprons, is mounted on the said pilot shaft which member can be traversed to move longitudinally along the shaft and can also rotate around or have angular movements about the axis of the shaft. This member or apron ior' aprons) ries the cutting tools and the feed -:to.the 001: is applied either by moving the tool carrying member or apron longitudinally along-the :said; pilot shaft, or moving it inan angular direction around the said shaft so @that the tools move either towards vor from the turning :axis the machine or work-piece, preferably in a vertical direction. The longitudinal or traversing move ment of the tool carrying member in the direction along and parallel to the said shaitis reffected by traversing means mounted on a member adapted to swing with thetoolccarnyi'ngmemher but incapable of slidingzalongpand'parallel to the axis of said pilotor' directingrshnft relatively to the base of the machine. "Ifhcangulamncvement of the tool, carryin member is controlled by gravity and -a. vertical reedsorewmeansrfor operating with, or associated with, the base of the machine.

The pilot or directing :shaft may have substituted therefor equivalentineans enablmg the tool carrying smemberzor aprcn'rto mirroredeither angular around afixedaxis, whichaxis is to hut-"some rhstanceisom the axis. of the V It :will heseen that one ohiect the "inventitm is in provide a machine tool in :which the member which carries the cutting tools mounted so as to be capable both of aronndand sliding along. (or heing red along) :a fixed whichsupports thememiber and which is parallel :to Hunt spaced some distance away from the :axis on. which the work-piece rotates, and also to .zprovlde roonrenient means wherebythese movements may doe wot-rolled.

Another object is to support the tool-carrying membenwlflch may he in the dorm of an ap on,

at mints widely spread or separated alone th axis on which it turns and With such wide-spreading or the said member is given greater rsolidity and relatively to its weight and stren th. and vibrations of the cutting tools are larg ly eliminated. Still a further object :is to place the said. upon; which tool camrhig memberrotates and slides at 'a considerable distance item the .axis

of rotation of the work-emcee or. the axis or the headstoc and support the .said member. :at another .mint adlacerrtto the latter axis-but preferably in 'iront said axis. 7

The front support is eomenientlvin the form or a vertical spindle operated; y'ialscrew" which not onlysunports the :frontend ofthe said member -or-.-anron b t adriusts and controls the elem-- tion of said front end, and thereby controls the feed and vdepth of "cut given to thecutting tools. This third point of zslll wrt is not, a fixed point of support butis in thenature of support :on the top oi a. vertical iced spindle hearing against a machinedpath on the tool carrying member so that the said member can freely slide above and on said spindle,

It "willthus h seen that the tool-carrying memberhas, the equivalent of a .three-pointsupport which will give it smart. stability and help to eliminate vibration, One important object h is to achieve this ..e1imination not vibration bypr vidins three wide-spread points. of support. Thisithird point of support'is advantageously in the front of the machine and in front of the work-piece to be turned and thus in front of the axis of turning and centre-line ofthe head-stock in which the work-piece is clamped and rotates. The other pointsof support, being alongthe axis about which the tool-carrying member rotates and slides, arest-the back of the machine;

axially along or to be rotated or moved trio-the 66 Another object of the-invention is so to arimposition with a practical absence of V ported.

tates and slides so that thecost of an ordinary lathe than the cost of a turret lathe.

. of the tool holders and tools carried' at-the end ofatool carrying member;=- 1

zontal plane. By so arranging this member its weight can be utilised to cause a tool fixed above the axis of rotation of the work-piece to efiect 5 a out upon the member upon the tool merely be;- ing lowered by the operation of the vertical feed- "ing' spindle. This enables cutting tools to be mounted upon the tool-.carrying'member or apron r both above and below the axis of rotation of the work-piece, and thus enables more than one cut ting tool to be used in sequence, the lower cutting tool being fed upwards by ftheloperation of;the" said vertical feed spindle, whilst the upper cut ting tool is lowered by easing oif said spindle and by gravity is forced against'th'e Work-pieceIthe =axisrthrough the. head-stock 2 and the work-piece 1 which will be'fixed therein is shown at AA.

depth of cut taken being however. ontrolledby; the movement of the said spindle. l

By the mounting of the tool-carrying member. or apron in the manner explained a further obj e'ct' 'is' achieved in that'the cutting tools maybe applied tothe work-piece so that theircutting edges are on the vertical plane upon whichitheturning axis of the work-piece lies. When this is done the cutting tools maybe so fixed on the carrying member or apron that bending stresses on the tools themselves may: be largely eliminated-be cause the'tools may beimore securely clamped overhang ing cantilever ends subjected to bending. This 3Q particularly applies to the tools. carriedon the apron itself below the work-piece which tools can, as'will hereafter be-explained,'be solidly sup-" Another main object of the invention is toprovide a construction according to which the toolcarrying member or apron can be fed or moved longitudinally along the axis about which it rov the cutting tools'carried; U thereby can be caused to perform the necessary turning operations. With this object in view the horizontal feeding of the tool carrying member in'a direction parallel to the turning axis of the work-piece and head-stock (and of the parallel 'turningand slidingaxis of the said-member itself) i i isiefiected by a'feeding mechanism carried upon a bracket, or its equivalent, which can-itsel-fturn on the same axis as that upon whichthe' said tool-carrying member turns and slides. :Thesaid bracket although turning on the same axis is so 50 mounted that itcannot itself slide along this axis. but only c'ausesthe tool-carrying member to slide therealong; r A further'object of the invention is to provide of performing certain-turning and machining operations very efficiently and with an absence of vibration, whilst at the same time the machine itself is very cheap to manufactureand requires in its fabrication the minimum of machining. It is indeed hoped to be able to make'a satisfactory machine which will'cost considerably less than and very much less The invention will nowbedescribed with 'ref- 60 erence to the accompanying drawingafinwhichi Fig. 1 is aplan of a formthe machine may'take Fig.2 is a side view of the machine with parts omitted? w 7o. Fig. 3 is adiagrammatic indication of'how a former may be used with'thismachiney f Fig. 4 isa sectional diagram to a larger scale 1 a very robust and stiif machine which is capable 55 through the Base Fig. 5 is a view of a modification of the machine, shown in plan, in which two tool carrying members are indicated instead of one;

Fig. 6 is a side view of this with parts omitted;

i '7 is an alternative view to Fig. 1 showing a plan of the machine in which the method of mounting the tool carrying member and the feed ing member are somewhat different; and

Fig. 8 is a side elevation of this machine with parts omitted. a Referring first to Figs, 1 and 2 the machine tool consists of a base I on which is mounted a .head istock 2i i .Thi's'h'ead-stock comprises a drivilig pulley 3, bearings 4, 4 and a collet or chuck 15 for holding the work in the machine. 7 The turning axis ofthe machine viz., the longitudinal and may either be fixed or may. revolve therein.

In 'many' cases itwill be better to make the said pilot or controlling shaft fixed, as for'example by the set screw 1. On this pilotor controlling shaft 6 is mounted. a tool carrying member 8 which canmove. both in-the 'angular direction aroundand longitudinally alongthe axis B-B;

which is the axis of the pilot or controlling shaft 6. This tool carrying member 8 may be in the form of'an apron,v for example as shown, and may roughly beof a triangular shape in plan. The tool carrying member 8 carriescutting tools 9 and) fixedein any convenient types of holders. One'of these tools I 0, is mounted under thew'ork piece,.and the others above the work-piece, as more clearly indicated in the enlarged sectional view shown injFig. 4. It Willbe seen that the cutting edges of these tools are approximately upon avertical plane C-C passing through the centre-lineof the head-stock 'that is to say are upon the vertical plane upon which the line A-A lies l f "The' movement or the tool'oarryihg member 3 in' an angular direction around the shaft 6 would then cause eitherthe tool 9 or the tool ill to engage with the work-piece Hf(see'F'ig. 4) to be turned. Theangular 'movementof the tool carrying member '8 is contzolled by the hand-wheel l2. which is fixed to ascrewed shaft i3 passing moved longitudinally by sliding axially along the axis BB"ofthe shaftB', being'moved by means of the hand-wheel? ilwhich 'is secured to a screwed shaft l5 carried'by amember or bracket l6 which is pivoted to swing about the axis 33-13 of the shaft 6. In the embodiment shown in Fig. l the bracket or member [6 lugs, IT, "IT, into which pivot pins [8/ l8, are screwed and fixed. These pivot pins have coned ends which enter axial'reces ses on the centre-line of the ,shaftlksothat thismember as swings about; the same axisB-Bas does'the to'ol ca'rrying member: 8. r In this particular instance; the:

* The tool carrying member I is provided with end macros shart; is so fixed in. it: hearinzs ormountings; 1,11, that it cannot. lmgitndinallm fimd hence although the member Hi can swing about the B-.--B it. czrmot. mote longitudinally along It fixed from longitudirial iaxialmovement) and canthereforeimpart such movement/to member fi' npon rotation of the hand-wheel M.

The screw i195 panes throughthe boss is which is fixed to the tool carrying member 8 and hence therotation :ofxthe hand-wheel l 4 causes the cutting .tools'fi and I tomove- .azxially, vim, parallel to axes A-A B--B and one or other of'these tools, when engaged with work-piece, will thus make the necessary out or 'will machine or turn the work-piece.

In Fig. 4 itwill be seen that the lower tool this shown as engaged with the work-"piecaand when the member 8 upon which :ltjsmormted is. moved axially, m. the-manner above indicated, the work-- piece will be turned by such tool.

Referring now toFiglflthe machine tool may also be used for copying intricate patterns. This can be done by replacing the spindle 13 of the wheel [2 by a template or former 20. A pointer 2| may be fitted to the tool carrying member 18 and rests upon the former 28. When longitudinaily (i. :e. axial) motion isimparted to .the tool carrying member, the front end 84: of the .said member is raised and lowered according to the shape of the former :as the member 8 is being moved axially, so that. the cutting tool moves similarly and turns the work-piece to the shape required.

Referring once again to the tool carrying .memher 8 of Figs. .1 and 2', it should he. noted that this member pivots on the shaft and issupported by the. bearings iin'the projections .22, 22, such manner :that. the member may bemoved angularly-around the rpiiohor-controlling'shait '6 or may slide along this-shaft. "This-shad; is a long shaft, for example, it'may he thezfull length of the machine, whereas it .is hit-ended that the axialmovemerit along this shaft of the tool carrying :memher will generally be :small. instance. apart of the. bearings 22, 22, is therefore unusually large, relatively to the required axial movement of the tool carrying member and this distance, centre to centre .of the bearings 22., 22, may conveniently be four, five .or :more than iiv-e times the axial distance through which "the. member 8 is intended to move. .This wide spacing of the bearings 22, 22, gives exceptional stifiness and stability to the member 8 and helps to check vibrations of the cutting tools carried thereby.

It will further be iobserredfrom Fig.'1that the tool carrying member or apron 8 is roughly triangular in shape and moreover has a point of support at the front end above "the :screw [3. This point is indicated at 23 in Fig.2. This is not a fixed point with reference to the member or apron 8,;as the memberor apron :8 slides upon and .is supported by this screwed shaft 13.. The lower side of the member or apron 8 may be machlned along the line along which the member slides above the screwedshaft 13.. This line is shown dotted at 2.4 in Fig. '1. In any case it will be seen that the point of support at the front end of the member 80,35 at some point along this line 24. At the same time the member 8 is also supported at its-twobearingsat 22, 22, and hence there is athree-point support 'of this tool carry ing member, which method oi support helps to avoid vibration in the member as th'ere is elimination of uncertainty :in manner :o'fdand cit-support. Thad}: thereiore mm whinhzis adapted admits-cutting tools with an elimination oi mvmdahle dilatation.

It will beseentthatiihe back end of-the-memupon the shaft 6 of considorahlerwidfh, Wham-compared with. fllaliiadf an ordinary saddle m moss slide or a. and hence efiect at near greatly reduced.

' now to Fig. i it will be seen that. an admiiage possessed by ihisnew :form tool is that the cutting tools to be mrmntodiso thaittthe length of the tool is: tangential to the work-piece, and hence the thrust on the tool is in line with the length oftthe tool. example, inzEig. at it. will be tnotedthat therwork-pieeeis zontaot with the lower tool MI; The mork-piene'is, in this figure, rotating clockwise is being turned. .The...top :of the tool andflength'nf the tool. is. tangential foo-the cylindricai cutibeingmde andtthe thruston the tool is in the'diredtion of the-arrow .25. This tool is ciampeddowntosthe upper surface of the tool carrying member 8 by use of the fastenings 215,261, and the tool is: most firmlyand solidly supported fmm underneath, so that there can belittle or nozbending moment on the tool, or if there-is any bendingmoment due to a slight lateral'thrust on :the'icool this is very small when compared with the bending moment which is appliedrtoiordinanyztools when fixed :to the saddle of a1 lathe.

The tool 1 0 which the lower tool of Fig. lis

brought'into-contact with the work-piece by rals-V ing the frontzendia of 'the tool supporting member 8, and the desired -cut can be adjusted by the operation of the'hand-w'heel 12 when a cylindrica'l en}; is beingma de i. e. when the work-piece is being" turned. After the desired machining operation is made with tool I'll, a further machiningoperation may be made with the upper tool 9 which is mounted and-clamped to the tool holder 'llibymealrs of-the clamping means 28, 28.

In this case-the toolis brought into operation by lowering the front end-of member '8 by'a desired amount ny the operation once again'of the handwheelll The 'member- 8 is'lowered owing to gravity and the-weight of the tool supporting member 8, or of the feeding member 16, or of both 'combined may be suohthat the tool Bwhen lowered by the operation of hand-wheel l2 isitself suiiicientlywei-ghted or loaded to efi-ect a cut of any desired depth.

Itwill -be noticed only one brother of the tools, to or- 9,'wi1loperate for-machining the work-piece at any one time.

As the cutting edgesof the tools H! and 9 are practically upon the vertical plane CC passin through the centre-line of the work-piece II, when a transverse cut is applied (as when parting or the bar'wthe force applied to the tool is in a horizontal direction at right angles to the work-piece or bar to be parted, and is along the length or the tool, "It will readily be realised that *this force is transmitted in a much more direct manner than that applied to a too] which projects through'the-transverse slide and saddle on thebed-o'f an'ordlnary standard lathe. There is thus no vertical bending of thelower tool and onl a small amount of bending on the upper tool, and it is found this method of mounting the tools eliminates spring in the tool and consequently there 'is no chatter. This results in smooth work and longevity of the cutting edge of'the' tool. I g g a "It should further be noted "that the turning swings are parallel to each other, Moreover in the embodiments shown these two axes lie approximately upon the. same horizontal plane.

Further, there is a considerable distance horizontally between these two axes AA and Be-B 'When therefore the tool carrying member 8 is moved angularlyaround the axis uponwhich it is mounted, or around the pilot and controlling shaft 5, the cutting edges of thetwo tools 9 and 10 move either up or down almost on the vertical plane CC through the turning axis of the work. piece. v

Turning now to Figs. '5 and: 6, a modification of the machine is shown inwhich a second tool carrying member or apron 29 is provided. This tool carrying member 2-9 is provided inthe illustration with bearings 30, 30, so that it also may turn about the shaft. 6. As these bearings 30, 30, are a close fit to, and adjacent to,-the bearings 22, 22

, of the tool carrying member 8, the two members 8 and 29 must travel together in the longitudinal or axial direction as they are caused to slide together alongthe shaft 6. However the upper.

member 29 may, if so desired, be swung up and out of use quite separately from the lower member 8, when it is no longer required. The front end 3| of this member 29 rests upon the upper surface of the member 8 and need not necessarily be fixed thereto. This end 3| may carry a tool, for example, it might carry a twist drill in a tailstock, or any other tool Whichit is desired to use.

If a twist drill or boring tool is fixed to 3|, this ma be aligned with the turning axis A- -A of the machine to make an axial bore in the work-piece.

However one is not limited in any way to the fixing of a particular type of tool in part 3|, but 7 variouscutting tools, one orimore in number, might be fitted. When no longer required the front end of the second member 29 may be lifted and swung right over the shaft 6, so as to hang from the shaft at the back'of the machine, and whilst the machine is being used, operating tools carried by the tool carrying member 8-, this member 29 then does no work but will merely slide back; and forward with the member Basthat member ismoved axially along the shaft.

7 Turning now to Figs. 7 and 8 another embodiment of the machine is shownin which the pilot and control shaft 6 has substituted therefor elongated trunnion pins Sa. These trunnion-pins are fixed to the tool carrying" member 8. They pass through bearings 1a, 1a

the base I of the machine and they enable the tool carrying member 8 not only to slide in these bearings la, la, but also to rotate "BB of these bearings,

which are supported on about the axis The feeding and axial-traversing member I6 is also mounted uponthese trunnion pins 6a, 6a having bearings 32 which embrace the'outward extensions of the pins 6a, 6a. The member or bracket It can therefore-be rotated in theangular direction around the pins 6a, 6a and thus'around the .axis 3-13, but is so formed that it embraces 3 B-'-B shall be both on the same horizontal plane;-

, shown in Figs. 1, 2, 5 and 6 axially along a fixed axis 'parallelto and spaced some distance machine.

Although in Figs. -1, 2 and 4 two cutting tools are shown as carried by the tool carrying member8, it will be obvious that lessor more tools might be carried by such nlembery'and one is not limited to the number or type of the tools. It is however desirable that at least one of the away from the turning axis of the tools carried by this member should be below the 7 work-piece so as to be raised against the workpiece, and at least one of the tools should be above the work-piece so as to .be lowered into contact 7 with the work-piece.

' The number of tools to be used will of course be according to the particular job which has to be I machined. 7

Although a tail-stock has been indicated as being carriedby the second tool supporting member illustrated in Figs-5 and 6, it would of course be possible to providei'a tail-stockfixed to the base I, as indicated at 33 in Fig. 7.

Although the pilot and may be, and most con veniently is, a simple turned shaft fixed in the bearings l, 1, and supported'from the base of the machine, it will be realised that with suitable modifications the shaft may be allowed to rotate in its bearings. If the shaft rotates it is not essential that the shaft should be circular in cross section in those parts, upon which the tool caronal section shaft but be so mounted that it will itself rotate about-the axis B,B, when such is necessary, for the tool carrying member to be moved in the angular direction around the axis of the shaft. Although it is convenient if a pilot or directing shaft is used that the feeding and axially traversing member l6 should be mounted on the end of the shaft or extensions of the shaft, this is not essential, as this member might be mounted in any other way so that it may rotate aboutthe same axis.

Although it has been indicated that'the. weight of the member 8 or 16, or both 8 and. IE; may be utilised to cause the upper tools to be applied to the work with suflicient force, it will'be understood'th-at such weight need 'not'be depended upon, as spring means'might be used, or other loadingv devices. be provided, whereby the neechine without departing from the scope'of the invention.

Any manner of supporting the members'fi and i6 may be provided 7 of rotatingabout an axis B-B.

It is not necessary that the two axes A"A' and so that they willbe capable this howeverhas been found 'to'be the best are closel the outer surfaces of thebearings 1a,"|a,

' which close contact prevents any-longitudinal movement of bracket 16' axially along this axis. The machine will'otherwise operate exactly in thesame'manner as described with reference to Figs. 1 and 2 and needs no further description. I It will of course be realised that the-scope of the invention is not restricted to the exact-embodiments shown, as other constructional details mightbe used enablingthe tool holder toimove rangement.

I claim: 7

1 A machine tool of the nature of a lathe and having-the capacity'of a simple non-screw-cutting lathe for turning, machining and axial drilling of a work-piece fixed therein, including the' combination of abase, a head-stock mounted on said base and in which the worlrr-piece maybe turnedya tool-carrying member} a mounting for said tool-carrying member on: which said memher is mounted formovement bothzlongitudinally controlling shaft 6' amass 'movement, said traversing means, beingmounted along and in an angular direction about 'a fixed axis parallel to and spaced from the turning axis of said head-stock, and a traversingsorew'mechanism' for enacting said longitudinal movement of said todl carryin'g member along said axis, said traversing screw mechanlsm-being'carried b a memberalso mounted to move a'ngdlarly about said fixed but to bo fixed against longitudinal movement therealong, said mounting and the member carries the-traversing screw mechanism being arranged in superposed rela ti-on'shi -with respect 'toeach other, said tool fur- 'ther comprising bearings on said fixed axis which said tool-carrying member is moun'tedysaid bearings being spaced apart at-distance at least equal to one half of the total length of the machine. l

2; A- machine tool of the nature of alathe and having the capacity of a simple non screw outting lathe fortnrni-ng machining and axialdrill:- mg of a work-'piecefixedtherein, including combination or a base, a licaad-stock'mounted o said base and in which wor1r=piece may be turned, a tool-carrying member, a mounting for said tool-carrying member on which said member ismounted for movement both longitudinally along and in an angular direction about a fixed axis parallel to and spaced from the turning axis of said head-stock, and a traversing screw mechanism for effecting said longitudinal movement of said tool-carrying member along said fixed axis, said traversing screw mechanism being carried by a member mounted to swing angularly with said tool-carrying member but to be fixed against longitudinal movement therewith, said mounting and the member which carries the traversing screw mechanism being arranged in superposed relationship with respect to each other.

3. A machine tool for eifecting machining operations ordinarily performed on a simple lathe, and having a base, a rotatable head-stock mounted upon said base for holding a work-piece to be machined, a pilot shaft also mounted upon said base in fixed parallel relationship to, but spaced away from, the turning axis of said headstock, a tool-carrying member pivotally mounted on said pilot shaft so as to be capable of being both traversed along said shaft and partly rotated about the axis of said shaftto enable tools carried thereby to perform a desired machining operation on the work-piece, a traversing means for effecting said traversing movement, said traversing means being mounted on a member adapted to swing with said tool-carrying member about the axis of said shaft but fixed against sliding movement along said shaft with said toolcarrying member, said tool-carrying member and the member which carries the traversing means being arranged in superposed relationship with respect to each other.

4. A machine tool for turning, facing up, cutting off and for effecting machining operations ordinarily performed on a simple lathe, and having a base, a head-stock mounted upon said base for holding and rotating a work-piece to be machined, a pilot shaft also mounted on said base in fixed relationship to, but spaced away from,

the turning axis of said head-stock, a tool-carrying member pivotally mounted on said pilot shaft so as to be capable of being both traversed along said shaft and partly rotated about the axis of said shaft to enable tools carried thereby to perform a machining operation on the work-piece, a

traversing means for effecting said traversing on a member adapted to swing with said toolcarryingmeirrber about the axis-cf said shaft but fixed againstsliding movement along said shaft with said *tool carryin'g membenand additional means for limiting and adjusting the angle of swing of said tool-carrying member about said pilot shaft, said tool-carryin member and the member which carries'the traversing means being arrangedin superposed relationshi with respect to each other.

' 5. A machine tool according to'claim- 4,111 which said additional means for limiting andadjusting the angle of swing of the tool-carrying member is a screw operated feed means. o. A machine tool capable or effecting turning and machining operations on a workpiece such as are ordinaril performed upon'a "simple nonscrew-cutting lathe, and comprising a base, a head-stock mounted on said base in which a work-piece maybe turned, a tool-carrying memberals'o mounted on said base and adapted to slide longitudinally along and partly "to rotate about a fixed axis in bearingscarrred by "said base, said fixed-axis being parallel to butspaced from the axis of rotation of the work-piece intheheadstock and being approximately in the horizontal plane thereof, and a traversing mechanism for effecting said longitudinal sliding movements of said tool-carrying member along said fixed axis, said traversing mechanism being carried by a member mounted to move angularly about said fixed axis, but to be fixed against longitudinal movement therealong, and said tool-carrying member having at least two bearing points widely spaced along said fixed axis, having a third point of support adjacent the vertical plane through the turning axis of the head-stock.

7. A machine tool according to claim 6, wherein said third point of support is farther from said fixed axis than is the axis of rotation of said head-stock.

8. A machine tool for effecting on a work-piece turning and machining operations such as are ordinarily performed upon a simple non-screwcutting lathe, and comprising a base, a headstock mounted on said base in which the workpiece may be turned, a tool-carrying member also mounted on said base both to slide longitudinally along and partly to rotate about a fixed axis on bearings carried by said base, said fixed axis being parallel to, but spaced from, the axis of rotation of the work-piece in the head-stock, a traversing screw mechanism for effecting said longitudinal sliding movement of said tool-carrying member along said fixed axis, said traversing screw mechanism being carried by a member mounted to swing angularly with said tool-carrying member but to be fixed against longitudinal movement therewith, and additional means for limiting and adjusting the angular position assumed by said tool-carrying member by rotation about said fixed axis and thereby controlling the vertical elevation of a tool carried by said tool-carrying member, said tool carrying member having three points of support, of which two points are on said fixed axis along which it is mounted to slide longitudinally and to turn, and the third point is adjacent the axis of rotation of said head-stock and is carried upon said limiting and adjusting means of said tool-carrying member, said tool-carrying member and the member which carries the traversing screw mechanism being arranged in superposed relationship with respect to each other.

9. A machine tool for elfecting turning and 7 ring a base, a head-stock mounted on said inwhich the work-piece may be turned, a carrying memberalso mounted on said base ed to slide longitudinally machining operations on a work-piece, comprisbase toolboth to slide longitudinally along and partly to rotate about a fixed axis on bearings supported by said .base,said axis being fixed parallel to, but spaced from, the axis of rotationof the work-piece in said head-stock, a traversing'means for effecting said longitudinal sliding movement of said toolcarrying member along said fixedaxis, said traversing means being carried by a member mounted .to move angularly about said fixed axisbut to be fixed against movement in the longitudinal direction of said axis, said tool-carrying member being provided with two pivot extensions mounted in said bearings, said pivot extensions being mounton said fixed axis in said bearings and to rotate, partly at least, in said bearings, said tool-carrying member and the member which carries the traversing means be-' 'ing arranged in superposed relationship with respect .to each other.

10. 'A machine tool according to claim 6, wherei in said tool-carrying member is approximately triangularin shape when viewed in plan and caradjacent one corner ries tool holders andtools, saidtool holders and one support of said tool-carryingmember being point of the triangle and the two bearings upon which said tool-carrying member slides and turns upon its fixed axis being adjacent the two other corner points of the triangle.

'11. A machine tool according to claim 4, in which said, tool-carrying member has at least two tool holders mounted thereon, and, when said member is in its working position, at least one said tool holder is positioned below the axis of rotation, of said'head-stock and at least one other tool holder is positioned so as to be above said axis of rotation. i V

12. A machine tool according to claim 4, having a screw operated vertical feed mechanism with 1 a screwed spindle for supporting said tcol-carrying member from said 

